1 files changed, 121 insertions, 0 deletions
diff --git a/arch/x86_64/lib/memcpy.S b/arch/x86_64/lib/memcpy.S
new file mode 100644
index 0000000..c6c4649
--- /dev/null
+++ b/arch/x86_64/lib/memcpy.S
@@ -0,0 +1,121 @@
+/* Copyright 2002 Andi Kleen */
+	
+	#include <asm/cpufeature.h>		
+/*
+ * memcpy - Copy a memory block.
+ *
+ * Input:	
+ * rdi destination
+ * rsi source
+ * rdx count
+ * 
+ * Output:
+ * rax original destination
+ */	
+
+ 	.globl __memcpy
+	.globl memcpy
+	.p2align 4
+__memcpy:
+memcpy:		
+	pushq %rbx
+	movq %rdi,%rax
+
+	movl %edx,%ecx
+	shrl $6,%ecx
+	jz .Lhandle_tail
+	
+	.p2align 4
+.Lloop_64:
+	decl %ecx
+	
+	movq (%rsi),%r11
+	movq 8(%rsi),%r8
+
+	movq %r11,(%rdi)
+	movq %r8,1*8(%rdi)
+
+	movq 2*8(%rsi),%r9
+	movq 3*8(%rsi),%r10
+
+	movq %r9,2*8(%rdi)
+	movq %r10,3*8(%rdi)
+		
+	movq 4*8(%rsi),%r11
+	movq 5*8(%rsi),%r8
+
+	movq %r11,4*8(%rdi)
+	movq %r8,5*8(%rdi)
+
+	movq 6*8(%rsi),%r9
+	movq 7*8(%rsi),%r10
+
+	movq %r9,6*8(%rdi)
+	movq %r10,7*8(%rdi)
+
+	leaq 64(%rsi),%rsi
+	leaq 64(%rdi),%rdi
+	jnz  .Lloop_64
+
+.Lhandle_tail:
+	movl %edx,%ecx
+	andl $63,%ecx
+	shrl $3,%ecx
+	jz   .Lhandle_7
+	.p2align 4
+.Lloop_8: 
+	decl %ecx
+	movq (%rsi),%r8
+	movq %r8,(%rdi) 
+	leaq 8(%rdi),%rdi
+	leaq 8(%rsi),%rsi
+	jnz  .Lloop_8
+
+.Lhandle_7:
+	movl %edx,%ecx
+	andl $7,%ecx
+	jz .Lende
+	.p2align 4
+.Lloop_1:
+	movb (%rsi),%r8b
+	movb %r8b,(%rdi) 
+	incq %rdi
+	incq %rsi
+	decl %ecx
+	jnz .Lloop_1
+	
+.Lende: 	
+	popq %rbx
+	ret
+.Lfinal:
+	
+	/* C stepping K8 run faster using the string copy instructions.
+	   It is also a lot simpler. Use this when possible */
+	
+	.section .altinstructions,"a"
+	.align 8
+	.quad  memcpy
+	.quad  memcpy_c
+	.byte  X86_FEATURE_K8_C
+	.byte  .Lfinal-memcpy
+	.byte  memcpy_c_end-memcpy_c	
+	.previous
+
+	.section .altinstr_replacement,"ax"
+ /* rdi	destination
+  * rsi source
+  * rdx count
+  */			
+memcpy_c:
+	movq %rdi,%rax
+	movl %edx,%ecx
+	shrl $3,%ecx
+	andl $7,%edx	
+	rep 
+	movsq 
+	movl %edx,%ecx
+	rep
+	movsb
+	ret
+memcpy_c_end:
+	.previous